Electric an-nunciator and circuit



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T. N. VAIL.

ELECTRIC ANNUNGIATOR AND GIEGUIT.

Patented June 10, 1884.

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T. N; VAIL. BLEOTRIO ANNUNGIATOR AND CIRCUIT. No. 300,168. Patented June10, 1884.

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TINTTE STATES PATENT Fries.

THEODORE N. VAIL, OF BOSTON, MASSACHUSETTS.

ELECTRIC AN'NUNClATOR AND CIRCUIT.

SPECIFICATION forming part of Letters Patent No. 300,168, dated June 10,1884.

Application filed January 30, 1884. (No model.)

To all whom it may concern: r

Be it known that I, THEO. N. VAIL, of Boston, in the county of Suffolkand State of Massachusetts, have invented certain Improvements inElectric Annunciators and Gircuits, of which the following is aspecificacentral-office apparatus of a telephoneexchange; and the objectof the said invention is to provide an annunciator or call-indicatingdevice which, when actuated by the manipulation of an operator at adistant station to drop a tag or shutter and give the signal, is capableof being reset through the instrumentality of electricity, and tofurnish,1noreover, a suitable and convenient arrangement of apparatusand circuit-closers, whereby the act of electrically resetting the saidannunciator may be accomplished by a person at a distance therefrom,either automatically by the act of connecting anytwo lines together, orby an independent manual operation. By this invention I am, for example,enabled to place the signalingannunciators in a telephoneexchange sohigh as to be out of reach, and thereby greatly economize space, or Imay accomplish what without my invention is unattainable-i. 0., placethe annunciators in a part of the room distant from the switch-boardoperator, yet retaining them under his control.

For the attainment of these purposes my invention consists in thefollowing devices and combinations: first, an annunciator capable. ofresponding to the changing electrical condition of a main circuit and ofgiving an absolute drop-signal, and furthermore provided with restingdevices actuated by an electromagnet in a local circuit; second, thesaid annunciator, or an instrument substantially equivalent thereto,combined with a main circuit and alocal circuit, one of the saidcircuits including the signal-giving and the other the signal-settingIna Jnet; third, thecon'venient arrangement of th, said signal-givingand resetting instrumentalities and the said main and local circuitswith reference to a switch board for connecting any two main circuitstogether, and two suitable circuit-closers for.

nunciator for use as a clearing-out signal. Fig. 4 is a diagram of theswitch-board connections of a single line and the electrical circuitsfor the annunciators, showing the automatic operation of the resettingdevice. Fig. 5 shows the main and local circuits complete and automaticand manual circuit -,closers therefor; Fig. 6 is a longitudinal'sectionof a connectingplug adapted for use in connection with theannunciator-circuit.

Referring now to Figs. '1 and 2, M is an .annunciator electromagnet,mounted upon a base, B, and provided with an armature, A, of the usualpattern, said armature being pivoted at f, and normally retracted fromthe cores 1) of the magnet by the spiral spring s.

By the pawl or hook detent h the drop signal or tag is held in placewhen the circuit is at rest and no electricity is passing therethrough.The said drop-signal turns freely upon its pivot 19, and when releasedby the pawl h falls by gravitation upon the stop B, as shown in Fig. 2.It is furnished with a lever-extension, L, projecting'rearward below thebase of the actuatingmagnet. The electro-magnet is, as shown, connectedin a main-line or sig naling circuit, l, extending from any desiredpoint. An auxiliary electro-magnet, M, which may be, but is notnecessarily, mounted on the same base B, is adapted by its terminalwires 0 c to be included in aseparate and independent circuit, and hasan armature, A, furnished with a long extension, L, engaged with theheel or lever extension of the dropsignal D. The armature A of theauxiliary magnet is. pivoted at f, and the heel L of the drop-signalserves as alimiting-stop therefor.

IOO

. as shown in Figs. 4 and 5. The auxiliarymag- When connected foroperationthe electroniagnet M in the signaling-circuit and theelectro-magnet Min the setting-eircuit-it is apparent that if anelectric current of sufiicient strength he passed through thecircuitwires Z, and consequently through the helices of the magnet M,the said magnet will become energized and attract the armature A to itscore 2), releasing the drop D, which then falls onto the stop B. I

Prior to my invention it has been proposed to reset the drop-signal bymeans of an auxiliary magnet, In the apparatus devised for that purposethe drop has been placed at the end of a long pivoted lever upheld by ahook at the end of the armature of the first magnet. The armature of theauxiliary magnet is attached to the short arm of the lever, the long armof which terminates in the tag or shutter. Such apparatus is heavy andnot suificiently delicate to insure certainty of operation. The weightof the drop-lever upon the armature-hook resists the attraction of themagnet and necessitates a strong impulse to release it. The apparatusherein described islighter and easier to operate and reset. Theelevation of the armature A,under the attractive influence of the cores1), causes a sharp and powerful depression of the lever end L, and this,engaging with the heel or extension lever L, acts thereon and lifts thesignal over the pawl h, thus resetting the drop and placing it inreadiness for another call.

Fig. 3 shows the lines connected through a flexible conductor with twoplug ends, the ends being inserted in the two line-circuits. In thedrawings the line or main-circuit wire Z, after passing through thesignaling-helices M, continues to the segmental plate 1 of theplug-socket E, from which it is continued through any other desiredapparatus to earth,

nets M are in the circuit of a local battery, L B, from which one wire,0, leads to the said electro-magnet, and another, 5, to the segmentalplate 4 of the plug-socket. From the opposite plate, 3, a wire, 0, leadsto the other side of the electro-magnet.

The plug which I preferably use is of the description shown in Fig. 6.The figure is a longitudinal section, and shows the construction. Theshank and handle H may be of any suitable nonconducting substance, whilea semicircular metal plate, d, electrically connected with thecord-conductor, is let into the upper part of the shank to make contactwith the line-segment, and a small metal plate, m, is let into the smallor lower end, the sole use of the latter being to make a temporary unionbetween the local-circuit sectional plates 3 and 4 while the plug isbeing inserted, and thus to close the circuit for an instant, permittingit again to be opened as soon as the plug is fully entered into thesocket. When a call is received and two lines are thereupon united bymeans of the plugs P and the connectingcord 0, the act of inserting eachplug will, by

bridging momentarily the space between the plates 3 and 4 and closingthe circuit, cause the electro-magnet M to actuate its armature andraise the drop-signah'; The original signaling-annunciator may then beused as a ring-off signal. These connections are all shown in Figs. 4and 5, and I have introduced'them into Fig. 3 only to show that by myinvention the original calling-annunciator may be,when resetautomatically by the insertion of the connecting-plug, readily used as adisconnecting-annunciator also.

Fig. 4 shows my :annunciator and setting device worked in conjunctionwith a multiple switch-board, or one in which the same line has aplug-socket at several diiferent places. The main line Z, after passingthrough the annunciator-helix, continues to the segment 1 of theplug-socket E of the first switchboard, thence by spring-jack t tosegment 2 of the same board, and by wire Z to the seg ments of thenextboard, and so on allthrough all of the switch-boards to the last,from which it passes to its earth-terminal G. From the local battery L Ba wire, 5, is led branching by wires 6 to segment 4 of each plug-socket,at each of which the circuit is normally open. From the other pole ofthe battery a wire, 0, leads to the resetting electro-magnet M, and fromthe said magnet a return-wire, 0', leads, by branches 7, to the segment3 of each of the plug-sockets of that line. The local circuit may bemade operative by the insertion of the plug, as already described. It isnot necessary to connect the battery L B to earth bywire w, as shown;but in practice this is done, as I am enabled thereby to use the samebattery for other purposes and with earth re-' turn-circuits. I haveshown in this figure the arrangement for but one main line; but it willbe at once understood by those skilled in the art that many other mainlines may be similarly connected, and that one local battery may servean unlimited number of resetting-mag nets. fers only in degree from thatshown in Fig. 4, and includes a manual circuit-closer and also thedistant signaling device.

Although I have so far described this annunciator as operated inconjunction with tele phone systems, it is applicable tosignalingeircuits of any character and length.

In Fig. 5, z is the signal-transmitting, and

The main X the signal-receiving, station. line Z, as hereinbeforedescribed, after passing through the annunciator-helix M, passes on tothe plug-socket segments, and then to the earth G; or, if the circuit iscontinuously metallic, the return is made, via wire Z, to thesignaling-station Z. At Z the circuit is provided with applianceswhereby the current from a suitable source of electricity may bedirected over it to actuate the signal at X. In the drawing I show abattery, M B, and a key, 70. The batteryat one end is connected with thekey-anvil Z, and atthe-other pole is either united to a ground-wire, G,or connected with The arrangement shown in Fig. 5 dif- IIO . groundwire.

the return-wirel. In either contingency its circuit is normally open,and may be closed onto the line by the depression of the key.

When the key is at rest, it presses upward against its backlimiting-screw, and then holds the main circuit closed round the batteryby wire 9, which branches from the return or In addition to thesegmental plates 3 and 4, at which the local circuit at the receivingstation is open, I provide a branch wire, 8, from the wire 0, whichleads to the key-anvil a, and a similar branch, 10, leading from thebattery-wire 6, and terminating in a key or press-button circuit-closer,K. By means of this key I am enabled to reset the annunciator if it bedropped a second time while the plug is in place.

Having now fully described my annunciator and its circuit arrangements,I claim- 1. An electric annunciator consisting, substantially asherei'nbefore described,of an electro-magnet for a signaling-circuit, anarmature therefor,and a drop-signal with lever-extension controlled bysaid armature, the electromagnet being adapted, when energized, toattract the armature and release the drop-signal, with an auxiliaryelectro-magnet adapted for .inclusion in an independent circuit, anarmature and lever therefor, said lever bearing upon and controlling thelever-extension of the drop-signal, whereby the said drop-signal may bereplaced by the attractive power of the auxiliary magnet exerted throughits armature and lever.

2. In a telephone'exchange system, the combination of two or more mainlines, a switchboard, connecting devices for connecting any two linestogether on said'switch-board, an

annunciator for each line, a localnormallyopen battery-circuit, and anauxiliary electromagnet therein adapted on the closing of its circuit toattract "its armature, and thereby reset said annunciator, saidbattery-circuit being connected with said switch-board,subst antially asdescribed, whereby the act of connecting any two lines together by meansof said connecting devices simultaneously closes said circuit, as setforth.

3. Ihe combination of the main lines, an-

nunciators, switch-board,. connecting devices,

such as switch-plugs, and resetting electromagnet in a normally-opencircuit connected with said switch-board, whereby the insertion of theswitch-plug in its socket to make a connection between two linesmomentarily closes said circuit long enough to energize said magnet andreset the annunciator, substantially as described.

4. In a telephone switch-board, the combination of plug-sockets andconnecting-plugs adapted to be inserted in the said s0ckets,with a localcircuit normally open at each plugsocket, and including a battery andelectromagnet, the said electro-magnet being attached ing the said localcircuit, for the purposes described.

In testimony whereof I have signed my name to this specificatiomin thepresence of two subscribing witnesses, this 17th day of January, 1884.

THEO. N. VAIL.

\Vitnesses Trros. D. LOOKWOOD, GEO. WILLIs PIERCE.

